A Study of Two-Weekly Intravenous Mircera for the Treatment of Dialysis Patients With Chronic Renal Anemia Not Receiving ESA Therapy.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of Two-Weekly Intravenous Mircera for the Treatment of Dialysis Patients With Chronic Renal Anemia Not Receiving ESA Therapy. (NCT00737711), a na phase 4 study. The primary outcome is Mean Change in Hemoglobin Concentration From Baseline to Week 16 of the Treatment Period.

2. Clinical Question

3. Trial Design

This was a completed Phase 4, single-arm, open-label study sponsored by Hoffmann-La Roche. The registry lists enrollment of 189 participants. The recorded study start was 2008-07, and primary completion was 2009-10. Allocation was listed as not applicable, consistent with the absence of a randomized comparator; masking was listed as none.

The intervention was intravenous Mircera, also identified as methoxy polyethylene glycol-epoetin beta. The brief summary describes a dose of 0.6 micrograms/kg every 2 weeks for 16 weeks, followed by 2 weeks of follow-up after the last treatment visit. The summary also states that anticipated time on study treatment was 3-12 months and that the target sample size was 100-500 individuals. These are registry descriptions, not evidence about each participant’s actual treatment duration.

The primary endpoint compared mean hemoglobin concentration at baseline with the mean at Week 16. The registry defines the analysis population as participants who received at least one dose of study drug, with data for participants available at the time of assessment. It also lists secondary outcomes concerning time in the 10.0-12.0 gram/deciliter hemoglobin range, adverse events, electrocardiograms, transfusions, anti-epoetin antibodies, and white blood cell count.

Because there was no control group and the study was open label, the design describes hemoglobin and safety outcomes during treatment, not a randomized estimate of treatment effect relative to an alternative.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The intent-to-treat (ITT) population included all participants who received at least one dose of the study drug. Data for participants available at the time of assessment is presented.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: Safety population included all participants who receive at least one dose of study medication.

6. Primary Endpoint

The registry lists the primary outcome as Mean Change in Hemoglobin Concentration From Baseline to Week 16 of the Treatment Period, measured over Baseline (Week 0) and Week 16.

The primary endpoint was the mean change in hemoglobin concentration from baseline (Week 0) to Week 16, measured in gram/deciliter (g/dL). In the registry’s definition, the change is the difference between the mean hemoglobin value at the last treatment-period visit and the mean value at baseline. The treatment period extended from baseline to Week 16.

Hemoglobin is a continuous measure, so a mean change summarizes the direction and average magnitude of the observed shift across the analyzed participants. Reporting the standard deviation alongside a mean can describe variability in individual values around that average. The registry identifies standard deviation as the dispersion measure for this endpoint, but the numerical mean change and standard deviation are not reported in the registry record.

In general, a baseline-to-follow-up change endpoint is used to describe how a measured characteristic differs over time within the study population. It does not by itself separate changes associated with the intervention from changes that might occur over time for other reasons. That distinction is especially important in a single-arm study, which has no concurrent control group. The endpoint therefore describes the observed hemoglobin change among the analyzed participants; without a reported numerical result, its magnitude and precision cannot be characterized.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous measure: hemoglobin concentration, expressed in gram/deciliter (g/dL). The registry specifies a mean and standard deviation, comparing baseline (Week 0) with Week 16. The endpoint is the difference between the mean at the last treatment-period visit and the mean at baseline. The numerical estimate and standard deviation are not reported in the registry record.

What does a mean change describe?

In general, a mean change condenses the observed changes into an average. It can be useful for describing the overall direction and magnitude of change, but it does not show the full distribution of individual responses. Participants may have changes that differ from the group average. The standard deviation describes the spread of observations around the mean; it is not a measure of the uncertainty in the estimated mean. The registry names standard deviation as the dispersion measure but gives no value for it.

What would a confidence interval add?

In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the analysis. A narrower interval indicates greater precision, while a wider interval indicates less precision. It does not show that all individual participant outcomes fall inside the interval. No confidence interval for the primary mean change is reported in the registry record, so its precision cannot be evaluated from the available endpoint information.

Why does the design matter?

This was a single-arm, open-label study with no randomized comparator. In general, a within-group change can reflect the course of the measured outcome during the study, but cannot by itself distinguish an intervention-associated change from other influences that may occur over time. A randomized control group can help address that limitation by providing a concurrent comparison, but none is described in this record. Thus, any interpretation of the primary endpoint would be descriptive of the observed participants rather than a randomized treatment contrast.

How should the analysis population be read?

The registry defines the intent-to-treat population as participants who received at least one dose of study drug and says that data available at the time of assessment are presented. This definition identifies who could enter the described population, but it does not state how many had an observed Week 16 result. In general, missing outcome data can affect an estimate if the participants with observed measurements differ systematically from those without them. The missing-data method and the number contributing to the primary endpoint are not reported in the registry record.

What do the planning assumptions mean?

The registry’s sample-size assumptions describe a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The planning target is defined as a stated fraction of the observed effect. For time-to-event outcomes, the description specifies total events using the Schoenfeld approach; other outcomes are described in participants per arm. These are planning assumptions, not evidence that the study had a particular probability of detecting an effect. The study itself was single arm, so the equal-allocation, two-arm illustration is not a description of its actual design. The numerical planning outputs and the effect value used for them are not reported in the registry record. Such planning values, where used, should not be called observed power.

The record does not describe a specific test for the primary endpoint, an adjustment method, or an inferential model. Those details are not reported in the registry record, and should not be inferred from the fact that the endpoint is a mean change.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("MIRCERA")
n   <- c(159)
m   <- c(2.11)
sp  <- c(1.3)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  MIRCERA  159  2.110  1.300  1.906  2.314

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 28 outcome measures, including the primary hemoglobin endpoint and secondary measures involving time and proportion in a hemoglobin range, adverse events, electrocardiograms, transfusions, anti-epoetin antibodies, and white blood cell count. When a study examines multiple outcomes, the chance of obtaining at least one apparently unusual result can increase if results are interpreted as though only a single outcome had been tested. In general, a statistical plan may address this through a hierarchy of outcomes or an adjustment for multiple testing.

The registry record does not report whether multiplicity was formally addressed, whether secondary outcomes were considered confirmatory or descriptive, or how any testing across outcomes was handled. It also does not report a statistical analysis plan or the primary endpoint’s numerical estimate and uncertainty. No correction or testing strategy should therefore be assumed.

For the analysis population, the record says that the intent-to-treat population included participants who received at least one dose, and that data available at the time of assessment are presented. It does not state how many participants had available Week 16 hemoglobin measurements, how missing values were handled, or whether any sensitivity analyses were conducted. In general, missingness can affect results when availability of an outcome is related to participant characteristics or outcome values. Without the missing-data procedures and assessment counts, it is not possible to judge the extent or potential influence of missing primary endpoint data.

The registry describes a sample-size planning illustration, but does not report the numerical planning outputs or the analysis details needed to connect them to the study’s actual single-arm design. These planning assumptions do not establish observed power or resolve uncertainties about missing data or multiplicity.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cardio-respiratory arrest (2.1%), pyrexia (2.1%), death (1.6%), lower respiratory tract infection (1.1%), pneumonia (1.1%).

The registry lists 189 participants at risk in the MIRCERA group for both serious and other adverse events. Serious adverse events affected 24 participants; other adverse events affected 11. These are reported participant counts, not counts of all event episodes. The registry’s listed serious-event terms include Cardio-respiratory arrest and Pyrexia at 2.1%, Death at 1.6%, Lower respiratory tract infection and Pneumonia at 1.1%, and Acute pulmonary oedema at 1.1%.

These figures are safety descriptions within a single treatment group, not comparative estimates. With no control arm, the record cannot show whether event occurrence differed from another treatment or from an untreated group. A listed event after treatment does not, by itself, establish that treatment caused it. The registry does not provide the context needed to interpret each event’s timing, recurrence, relationship assessment, or clinical course. The separate deaths count is not reported in the registry record, even though Death appears among the listed serious-event terms. The terms and percentages should therefore be read as selected registry summaries, not as a complete causal assessment.

13. What the Result Does, and Does Not, Mean

The study asks a clinically focused descriptive question: how hemoglobin concentration changed from baseline to Week 16 among dialysis patients with chronic renal anemia who were not receiving ESA therapy and received intravenous Mircera. The registry identifies the endpoint and describes the treated population, schedule, and safety reporting. However, it does not report the numerical primary mean change or its standard deviation. The size, direction, and precision of the primary endpoint therefore cannot be judged from the registry record.

The design also limits what any observed change could establish. A single-arm study does not provide a concurrent comparison against another treatment or usual care. In general, changes over time may reflect more than the intervention under study, so a before-and-after observation does not isolate a causal effect. Open-label conduct is another feature to consider, although the record does not report how it affected outcome measurement or event reporting.

The safety counts describe events reported in the MIRCERA group. They are not a comparison of relative safety, and selected serious-event terms do not prove that the study drug caused those events. The record’s safety summary also does not supply all the clinical context that would be needed to interpret individual events.

Accordingly, the registry supports an understanding of the study’s question and broad design, but not a quantitative conclusion about the primary hemoglobin result or a controlled estimate of treatment effect. The absence of those results in the registry record should not be mistaken for evidence that the endpoint showed no change. It means that the result and its uncertainty cannot be assessed from this record.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of the distinction between an endpoint’s definition and its reported result. The registry clearly defines a mean change in hemoglobin from baseline to Week 16 and identifies the standard deviation as the dispersion measure. Yet the numerical estimate and variability are not reported in the registry record. Knowing what was measured is not the same as being able to evaluate what the measurement showed.

The single-arm design also makes the distinction between description and comparison central. A mean change can describe the course of hemoglobin in the treated study population, but, without a control group, it cannot provide a randomized contrast. This is a useful interpretive boundary for clinical researchers: the statistical form of an endpoint does not remove the limitations imposed by the study design.

Safety reporting illustrates a related point. Participant counts and selected event-term percentages convey information about observed events in the treated group, but they do not establish comparative risk or causality. Their interpretation depends on denominators, event definitions, follow-up, and clinical context; not all of these details are reported in the registry record.

The record also lists multiple outcome measures and a planning-illustration description. These do not substitute for a reported statistical plan, numerical endpoint results, or a defined approach to missing data and multiplicity. Separating those elements helps prevent planning assumptions from being mistaken for observed evidence and clarifies which conclusions the registry can support.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The principal limitation for interpreting the primary endpoint is that its numerical mean change and standard deviation are not reported in the registry record. Without an estimate and measure of variability, neither the magnitude of the observed change nor its precision can be assessed. A confidence interval is also not reported.

The study was single arm and open label, with no randomized comparator. It can describe outcomes among participants treated during the study, but cannot estimate a randomized difference against another intervention or control condition. The record does not report details on how open-label conduct may have influenced measurement or reporting.

The registry defines the intent-to-treat population as participants who received at least one dose and says that data available at assessment are presented. The number with a Week 16 measurement, the extent of missing data, and the methods used to handle missing observations are not reported in the registry record. Statistical tests, confidence-interval methods, and any analysis plan are also not reported.

The record lists 28 outcome measures but does not describe how multiplicity was handled or clarify the inferential status of secondary outcomes. Safety summaries provide participant counts and selected serious-event terms, but do not establish causality or give full event-level context. The deaths count is not reported in the registry record. Finally, the planning assumptions describe a two-arm illustration, whereas the trial itself was single arm; the numerical planning outputs are not reported in the registry record and should not be interpreted as observed power.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of Two-Weekly Intravenous Mircera for the Treatment of Dialysis Patients With Chronic Renal Anemia Not Receiving ESA Therapy. — NCT00737711.
• Registry record last updated 2016-06-02; status last verified 2016-04.
• Results first posted 2016-06-02.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT00737711 was a completed Phase 4, single-arm, open-label study sponsored by Hoffmann-La Roche. It enrolled 189 dialysis patients with chronic renal anemia who were not receiving ESA therapy. The described intervention was intravenous Mircera, 0.6 micrograms/kg every 2 weeks for 16 weeks, with follow-up planned for 2 weeks after the last treatment visit.

The primary endpoint was mean hemoglobin change from baseline (Week 0) to Week 16. The registry describes an intent-to-treat population based on receipt of at least one dose and reports data available at assessment, but the primary numerical result and its standard deviation are not reported in the registry record. Safety summaries list serious adverse events affecting 24 participants and other adverse events affecting 11. With no comparator, the design supports descriptive interpretation rather than a randomized treatment comparison.